GSK Sues Spectrum Over Imitrex

GlaxoSmithKline (GSK) has filed a patent infringement lawsuit in federal court against Spectrum Pharmaceuticals to prevent Spectrum from developing a generic version of GSK's migraine drug Imitrex.

GSK filed suit in the U.S. District Court for the District of Delaware to meet the required 45-day window called for under the Hatch-Waxman Act. Under Hatch-Waxman, if an abbreviated new drug application (ANDA) applicant files a Paragraph IV certification and notifies the patent holder, the patent holder has 45 days to sue the applicant for infringement.

Spectrum initiated a challenge to GSK's Imitrex (sumatriptan succinate) injection in 6 mg/0.5 mL doses when it filed an ANDA with a Paragraph IV certification in October 2004. The FDA notified Spectrum that it had received the Paragraph IV certification in January. GSK's patent on Imitrex is set to expire Feb. 6, 2009.